Rev 1.0
1/27/14
34
34
Reference Guide
Interfaces
The USR3500 GPS antenna must meet the requirements specified in the table
below.
Table 23. GPS Antenna Specifications for USR3500
Characteristic
GPS L1
RX Frequency
1575.42 MHz
RF Impedance
50
Ω
VSWR Rx max
1.5:1
LNA Bias Voltage
5V
LNA Current
Consumption
40mA MAX
Polarization
Linear, vertical
Typical radiated
gain
0dBi in one direction at least
3.2.2.3.
GPS Specifications for USR3500
Note:
These specifications are preliminary targets that are subject to change without notice. Actual GPS
functionality depends on the firmware version and module configuration.
The USR3500 provides the GPS features listed in the following sub-sections. This
GPS feature can be used through AT commands provided by the Extended Open AT
application (which is pre-loaded at the factory) or from a custom Open AT application
using Location Library.
3.2.2.3.1.
Standalone GPS
•
Leading standalone/autonomous GPS performance
•
-145 dBm cold start sensitivity
•
-153 dBm hot start sensitivity
•
-155 dBm tracking sensitivity
•
< 45 second average
cold start TTFF (Time To First Fix) in open air
•
< 3 second average super hot TTFF in open sky
•
< 10 m accuracy in open sky
Note:
For optimum performance, the modem should be registered on the GSM/UMTS network, but does
not need to be on an active data or voice call.
3.2.2.3.2.
gpsOneXTRA
TM
•
Enables enhanced standalone GPS operation by downloading < 40 kB file
from a server on the Internet
•
Performance closer to UE-based operation than traditional standalone GPS
operation